Type 606 Metal Bellows Seal Replacement

Type 606 replacement: check fit, drive and duty

This metal bellows seal is offered for replacement enquiries involving John Crane Type 606 pump seals. Start with the existing assembly drawing: a matching model number and shaft diameter alone do not establish a suitable replacement.

Published operating range

These are separate selection limits, not a guarantee that every maximum can be reached at the same time. Confirm the proposed size, materials, pressure reference and operating duty on the quotation. Ratings published for the original manufacturer’s seal must not be substituted for the replacement supplied here.

Three checks before approving a 606 replacement

1. Record installed dimensions, not just the removed seal length

Measure the shaft or sleeve at the seal position, the stationary-seat outside diameter and thickness, and the available chamber space. Identify the installed working length on the assembly drawing. A removed bellows assembly may relax, so its free length should not be used as the installation setting. Label every measurement in inches or millimetres and include the seat retention arrangement.

2. Compare the drive components

The original Type 606 incorporates drive lugs beneath the bellows. For an enquiry, photograph the existing drive components and show their engagement on the drawing. Ask for the corresponding arrangement to be identified on the proposed replacement drawing. A similar bellows profile does not establish that the torque-transmission details match.

3. Describe what happens between running and restarting

Alongside the liquid name, normal temperature, seal-chamber pressure and shaft speed, record whether the liquid thickens when cold, hardens during a stop or leaves deposits. State the duration of shutdowns and any existing heating, flushing or quench arrangement. These details make an enquiry more useful than a maximum-temperature figure alone.

Materials to specify on the quotation

• Seal faces: carbon, silicon carbide, sintered silicon carbide and tungsten carbide are listed options. Identify both the rotating and stationary face materials rather than requesting “SiC” alone.
• Secondary seals: flexible graphite or FFKM, subject to the selected configuration and fluid compatibility.
• Bellows and hardware: the listing includes 304/316 stainless steel, Hastelloy C and Inconel alloy options. Confirm the exact bellows alloy and hardware grade separately.

A hard face pair alone does not establish suitability for particles or crystallising liquids. Review the complete seal arrangement and supporting system for those duties. The material list also does not mean that every combination is suitable across the full published range.

Application review

Enquiries may involve hot-oil circulation, heat-transfer fluids, chemical transfer or refinery process pumps. Treat these as starting points for selection: chemical compatibility, lubrication at the faces, pressure changes and restart conditions must be reviewed for the actual pump.

A metal bellows provides axial flexibility without a dynamic secondary O-ring sliding along the sleeve. This addresses one potential source of hang-up, but it does not make the complete seal immune to deposits, dry running or an unsuitable installation.

Build a useful Type 606 enquiry package

• Pump manufacturer and model, existing seal identification and quantity.
• Assembly drawing with shaft size, working length, stationary-seat dimensions and drive details.
• Photos of the complete seal and mating parts, including any visible wear or deposits.
• Process liquid, operating pressure and temperature, shaft speed, and start-up/shutdown conditions.
• Known material grades and the required supply scope: rotating unit, seat, complete component assembly or cartridge proposal.

Mark unknown dimensions or materials as unknown instead of estimating. Keep the removed seal and mating parts available until the proposed replacement configuration is agreed.

Send your Type 606 drawing and operating conditions, or compare models in our metal bellows seal range.

Type 606 replacement questions

Can a Type 609 replace a Type 606?

Do not assume interchangeability. Compare the drive arrangement, working length, seat and complete installation dimensions, then review the duty. If the removed seal is marked 609, start with our Type 609 replacement page.

What if I have only photographs of the old seal?

Photographs help identify the parts to check. Include views of the stationary seat and drive components, then supply measured dimensions or an assembly drawing before approving fit. A photograph alone cannot confirm installed working length.

Is this an original John Crane seal?

This page describes a replacement product enquiry. John Crane and Type 606 identify the original seal being replaced; the proposed replacement configuration and compatibility must be confirmed before ordering.